sodium-nitrite and Hemolysis

Systemic cell-free hemoglobin (Hb) released via hemolysis disrupts vascular homeostasis, in part, through the scavenging of nitric oxide (NO). Sodium nitrite (NaNO(2)) therapy can attenuate the hypertensive effects of Hb. However, the chemical reactivity of NaNO(2) with Hb may enhance heme- or iron-mediated toxicities. Here, we investigate the effect of NaNO(2) on the central nervous system (CNS) in guinea pigs exposed to systemic cell-free Hb. Intravascular infusion of NaNO(2), at doses sufficient to alleviate Hb-mediated blood pressure changes, reduced the expression of occludin, but not zona occludens-1 (ZO-1) or claudin-5, in cerebral tight junctions 4h after Hb infusion. This was accompanied by increased perivascular heme oxygenase-1 expression, neuronal iron deposition, increased astrocyte and microglial activation, and reduced expression of neuron-specific nuclear protein (NeuN). These CNS changes were not observed in animals treated with Hb or NaNO(2) alone. Taken together, these findings suggest that the use of nitrite salts to treat systemic Hb exposure may promote acute CNS toxicity.

Topics: Animals; Central Nervous System; Central Nervous System Diseases; Claudins; Guinea Pigs; Hemoglobins; Hemolysis; Humans; Male; Membrane Proteins; Occludin; Oxidation-Reduction; Phosphoproteins; Sodium Nitrite; Zonula Occludens-1 Protein

Hemoglobin (Hb) potently inactivates the nitric oxide (NO) radical via a dioxygenation reaction forming nitrate (NO(3)(-)). This inactivation produces endothelial dysfunction during hemolytic conditions and may contribute to the vascular complications of Hb-based blood substitutes. Hb also functions as a nitrite (NO(2)(-)) reductase, converting nitrite into NO as it deoxygenates. We hypothesized that during intravascular hemolysis, nitrite infusions would limit the vasoconstrictive properties of plasma Hb. In a canine model of low- and high-intensity hypotonic intravascular hemolysis, we characterized hemodynamic responses to nitrite infusions. Hemolysis increased systemic and pulmonary arterial pressures and systemic vascular resistance. Hemolysis also inhibited NO-dependent pulmonary and systemic vasodilation by the NO donor sodium nitroprusside. Compared with nitroprusside, nitrite demonstrated unique effects by not only inhibiting hemolysis-associated vasoconstriction but also by potentiating vasodilation at plasma Hb concentrations of <25 muM. We also observed an interaction between plasma Hb levels and nitrite to augment nitroprusside-induced vasodilation of the pulmonary and systemic circulation. This nitrite reductase activity of Hb in vivo was recapitulated in vitro using a mitochondrial NO sensor system. Nitrite infusions may promote NO generation from Hb while maintaining oxygen delivery; this effect could be harnessed to treat hemolytic conditions and to detoxify Hb-based blood substitutes.

Topics: Animals; Biosensing Techniques; Blood Pressure; Blood Substitutes; Dogs; Dose-Response Relationship, Drug; Hemodynamics; Hemoglobins; Hemolysis; Infusions, Intravenous; Male; Mitochondria, Liver; Models, Animal; Nitric Oxide; Nitrite Reductases; Nitroprusside; Rats; Rats, Sprague-Dawley; Sodium Nitrite; Time Factors; Vascular Resistance; Vasoconstriction; Vasodilation; Vasodilator Agents

A method for the determination of bisphenol A (BPA) in blood was investigated using high-performance liquid chromatography-electrochemical detection (HPLC-ED) with solid-phase extraction. When BPA at the concentrations of 25-100 ng/ml were added to whole blood, BPA recoveries were 26-48%. When BPA was added to water, plasma or hemolyzed red blood cells (H-RBC), BPA recoveries in water and plasma were almost similar (94%). However, the recovery in H-RBC was very low (36-46%). When BPA and plasma were added to H-RBC, the recovery was 70-85%. In authentic bovine metHb solution, BPA decreased depending on the metHb concentration, however, BPA recovery in the solution added with more than 17% plasma was higher than that in metHb only. These suggest that metHb influences the BPA recovery in whole blood. However, an accurate determination of BPA using HPLC was easily made possible by separating RBC from plasma.

Topics: Animals; Benzhydryl Compounds; Chromatography, High Pressure Liquid; Electrochemistry; Erythrocytes; Estrogens, Non-Steroidal; Hemolysis; Humans; Methemoglobin; Phenols; Reproducibility of Results; Sheep; Sodium Nitrite

Nitrogen oxide, which is produced by activated macrophages, has been demonstrated to possess anti-tumor activity. We report herein the synergistic effect of sodium nitrite (NO2-) and/or sodium nitroprusside (SNP) on lysophospholipid (LysoPL)-mediated cytolysis. The incubation of 51Cr-labeled mouse melanoma (B16) cells with NO2- alone for 3 h at 37 degrees C did not induce cytolysis. On the other hand, NO2- significantly enhanced the cytolysis of B16 cells in the presence of lysophosphatidylcholine (LysoPC; 2.0 microM). A similar effect of NO2- on B16-cytolysis was also observed in the presence of 1-O-alkyl-sn-glycero-3-phosphocholine (LysoPAF). In addition, SNP (0.05-0.5 mM) synergistically enhanced B16-cytolysis in the presence of LysoPC. However, nitrate had no effect on the cytolysis of B16 cells treated with LysoPC. Furthermore, NO2- synergistically enhanced the hemolysis of sheep erythrocytes in the presence of LysoPC, but not in the presence of an anti-sheep erythrocyte antibody and complement. These findings suggest that NO2- directly affects membrane damage in the presence of LysoPL.

Topics: Animals; Cell Division; Cell Membrane; Drug Synergism; Erythrocytes; Hemolysis; Lysophosphatidylcholines; Lysophospholipids; Macrophages; Melanoma, Experimental; Mice; Nitric Oxide; Nitroprusside; Sheep; Sodium Nitrite; Tumor Cells, Cultured

The variables affecting the formation and stability of intracellular methaemoglobin were examined. A method is proposed for the preparation of intracellular methaemoglobin specimens.

Topics: Anticoagulants; Erythrocytes; Hematoma; Hemolysis; Humans; Magnetic Resonance Imaging; Methemoglobin; Osmotic Fragility; Sodium Nitrite; Temperature; Ultrasonography

Topics: Adult; Erythrocyte Membrane; Hemoglobins; Hemolysis; Humans; Hydrogen Peroxide; Hydroxylamines; In Vitro Techniques; Membrane Lipids; Methemoglobin; Oxidation-Reduction; Oxyhemoglobins; Pentanes; Sodium Nitrite

The red blood cell hexose monophosphate shunt (HMS) and proteolytic responses to several concentrations of Methylene Blue or sodium nitrite were measured. The results suggested two distinct mechanisms for activation of the HMS: (1) nitrite treatment increased HMS activity in response to oxidative challenge to red cell protein; (2) Methylene Blue treatment activated HMS without injurious oxidative challenge. Nitrite-treated cells actively degraded protein, whereas Methylene Blue-treated red cells did not activate proteolytic systems that degrade oxidized red cell protein. These observations are relevant to proposed in vitro systems for evaluation of drug hemolytic toxicity potential on the basis of HMS stimulation capacity.

Topics: Adult; Erythrocytes; Hemolysis; Humans; In Vitro Techniques; Male; Methylene Blue; Oxidation-Reduction; Pentose Phosphate Pathway; Peptide Hydrolases; Sodium Nitrite

The addition of sodium nitrite to washed bovine erythrocytes incubated in buffered saline resulted in the formation of methemoglobin with a decrease in the concentration of 3-N-ribosyluric acid. The oxyhemoglobin in hemolysates prepared from bovine red cells which contained high concentrations of 3-ribosyluric acid was oxidized to methemoglobin more slowly than oxyhemoglobin from cells with low levels of 3-ribosyluric acid. Oxyhemoglobin from hemolysates that were dialyzed was oxidized more rapidly than oxyhemoglobin which was not dialyzed. 3-Ribosyluric acid, glutathione, uric acid, and ascorbic acid prevented the oxidation of oxyhemoglobin by nitrite. Uric acid protected oxyhemoglobin at the lowest concentration, followed closely by ascorbic acid, 3-ribosyluric acid, and glutathione. Hydrogen peroxide enhanced the oxidation produced by nitrite; this effect was also prevented by the four antioxidants used.

Topics: Animals; Ascorbic Acid; Cattle; Erythrocytes; Glutathione; Hemolysis; Hydrogen Peroxide; In Vitro Techniques; Methemoglobin; Nitrites; Oxidation-Reduction; Oxyhemoglobins; Ribonucleosides; Sodium Nitrite; Uric Acid